German Published Patent Appln. No. 196 04 134 describes a method and a device for controlling a brake system of a motor vehicle having an electric drive. When there is a braking of the vehicle using the electric drive for the simultaneous charging of a battery, the hydraulic braking moment applied to at least one wheel by the at least one wheel brake cylinder of the hydraulic brake system is to be reduced/deactivated, despite an actuation of the brake pedal. For this purpose, the pressure medium, displaced out of the master brake cylinder to the wheel brakes by the actuation of the brake pedal, is to be counteracted in that, by opening the outlet valves of the hydraulic brake system, the pressure medium displaced out of the master brake cylinder is transferred into at least one storage chamber via the at least one wheel brake cylinder. In this way, a regenerative braking carried out by the electric drive is to be maskable.